Blindsight vs. Mirror Image (figment)

[eamon]

When mirror image says "An attacker must be able to see the images to be fooled. If you are invisible or an attacker shuts his or her eyes, the spell has no effect. (Being unable to see carries the same penalties as being blinded.)" it's something that (as always) you need to interprete in context. In normal situations, in which creatures normally locate things by sight, clearly, this holds true. You should not construe the phrase to mean that the auditory effects of the spell are suppressed when someone closes their eyes.

The question is whether "When you and the mirror image separate, observers can’t use vision or hearing to tell which one is you and which the image." means that there is some auditory component, sufficient to merely fool the crude hearing of an average human, or that the auditory component is sufficient to fool blind-sight-quality hearing.

If someone walks past you, you'll notice that ambient noises not made by the passerby are significantly effected by the passing person. Simple passive "keen hearing" is just like echolocation in that it relies heavily on sound "bouncing off". I would avoid differentiating types of blind-sight based on whether they're "keen-hearing" or "echolocation" based, as it's a very fine distinction which you'll need to invent (it's not stated in creature's blind-sight descriptions), and makes no real-world sense either.

So I see three real options:
(1) Mirror image is not sufficient to fool blind-sight as the fake auditory figments don't do reflection and so on accurately enough
(2) Mirror image can fool blind-sight based on hearing, even if the blind-sighted creatures closes it's eyes. Of course any creature can randomly swing at a square for a 50% mischance; but then they won't be terminating any images when they do so.
(3) Mirror image can fool all blind-sight, as tremorsense and scent alone are not sufficient to do more than locate the square someone is in, which is possible anyhow (normally).

For simplicity I would prefer (1) or (3).

Regarding (3), can anyone think of a creature which has a blind-sight ability completely without auditory component? That would rule out option (3).

Against option (3): compared to other illusions, a blind-sight fooling illusion is rather powerful for a 2nd level spell (compare to major image, a 3rd level spell)
Against option (2): complex to administer, asking for rule discussions.
Against option (1): Seems counter to the spell description which names hearing as one of the fooled senses.

I think I'm leaning towards option 3, nice and simple and matches the spell-description. it's a little powerful, but not horribly so, I think.

 

[eamon]

But Echolocation is not the same as Keen Hearing.

Not only is it a difference sense (as listed in the SRD), but Echolocation does not *have* to rely on hearing. For all we know there's a special echolocation chip (Nacho Cheese no less) in some monsters (remember, physics is a house rule).

What do you mean echolocation does not have to rely on hearing? Then it's not echolocation. Maybe there's some other "silent sonar" sense, but plain old echolocation is echolocation. It uses echos. Of sound. Which you need to hear. Not much else to it is there?

 

[Matthias_Gloom]

What's the logic behind echolocation having some special status?

If you shine a bright cone of light at the mage and his four images: all of them appear to reflect light, all of them cast a shadow.

If you emit a high pitched directional sound at the mage and his four images: all of them appear to reflect sound.

Doesn't that make sense? Else a bullseye lantern becomes your first line of defense.

Cheers, -- N

Mirror images may be capable of 'generating' sound within the context of the spell, but being able to 'reflect' sound would require substance, which your typical illusory image, by definition, doesn't have.
Echolocation seems like a perfectly viable way of 'not seeing' the mirror images.

 

[Nifft]

Mirror images may be capable of 'generating' sound within the context of the spell, but being able to 'reflect' sound would require substance, which your typical illusory image, by definition, doesn't have.
Echolocation seems like a perfectly viable way of 'not seeing' the mirror images.

How is this different from being able to reflect light? If figment has no substance, how does it cast a shadow? (And if the image fails to cast a shadow, you don't need 'echolocation' to find the real dude.) Seriously, it makes the same amount of sense:

Mirror images may be capable of 'generating' light within the context of the spell, but being able to 'reflect' light would require substance, which your typical illusory image, by definition, doesn't have.
A bullseye lantern seems like a perfectly viable way of 'not seeing' the mirror images.

See? When you fall back on what "makes sense", magic falls apart in many different ways.

(Why can't the spell just do what it says it does? It's magic, not highly advanced physics.)

Cheers, -- N

 

[Nail]

(Why can't the spell just do what it says it does? It's magic, not highly advanced physics.)

..because that would require reading the spell description, Nifft. No one wants to do that.

 

[Matthias_Gloom]

What about grenades?

 

[Nifft]

What about grenades?

Figments seem to react normally to area spells (such as looking like they’re burned or dead after being hit by a fireball).

Spell descriptions are so useful!

Cheers, -- N

 

[Matthias_Gloom]

Spell descriptions are so useful!

Cheers, -- N

They certainly are!

The figments stay near you and disappear when struck...Any successful attack against an image destroys it.

Grenades, alchemists' fire and acid, for example, are hardly spells. They do non-magical damage. Would not the images disappear as if struck?

 

[Mistwell]

Wow. I never even thought about how a single alchemist fire or flask of oil would foil all the images in a mirror image (provided you at least hit close to the target square with a touch attack - which I guess would be an AC 10). That's interesting.

 

[prospero63]

Here is how I would adjudicate it.

Mirror Image vs. Blindsight. The keys are the following from Mirror Image:

"When you and the mirror image separate, observers can’t use vision or hearing to tell which one is you and which the image"

and the following from Blindsight:
"Some creatures have blindsight, the extraordinary ability to use a nonvisual sense (or a combination of such senses) to operate effectively without vision. Such sense may include sensitivity to vibrations, acute scent, keen hearing, or echolocation"

So let's break that down:

Vision - advantage Mirror Image
Sound - advantage Mirror Image
Echo location - advantage Blindsight (figments must be perceived, you don't do that with Blindsight)
Vibrations - advantage Blindsight
Acute Scent - advantage Blingsight

So the nuts of it are Blindsight renders Mirror Image worthless. Lifesense similarly does the same thing. "just as if it possessed the blindsight ability".

We got absolutely beat upon once by overlooking scent and lifesense when we tried to sneak into a keep that had some undead types hanging around. The irony is we had the means to deal with both, but completely dropped the ball...

HTH.